%I #13 Apr 07 2016 08:26:47
%S 1,2,3,4,6,9,11,14,18,22,26,30,35,41,46,51,58,65,71,78,86,94,102,110,
%T 119,128,138,147,157,167,178,189,200,211,223,236,248,260,273,288,301,
%U 314,328,344,358,373,388,405,420,436,452,471,487,504,521,541
%N Unique increasing sequence satisfying a(n) = a(n-4) + c(n-4); where c( ) is complement of a( ).
%C Here "complement" refers to the numbers not in the sequence.
%H Ivan Neretin, <a href="/A022956/b022956.txt">Table of n, a(n) for n = 1..10000</a>
%t Fold[Append[#1, #1[[#2]] + Complement[Range[Max@#1 + 1], #1][[#2]]] &, {1, 2, 3, 4}, Range[52]] (* _Ivan Neretin_, Apr 05 2016 *)
%Y Cf. A005228 and references therein.
%K nonn
%O 1,2
%A _Clark Kimberling_
%E Missing term a(44)=344 added by _Ivan Neretin_, Apr 05 2016